The scheduled events are based on interval, not a specific time. When the interval is exactly 24 hours this can be confusing. The scheduled event was probably scheduled in another daylight savings period at a certain time and it will keep running at 24 hour intervals, meaning it might be an hour later or earlier on a day when daylight savings has changed.
If your scheduled events must be triggered at a certain time instead of being interval-based, you could consider running 2 of them and having a check in the microflow seeing in which daylight savings time you are and simply not executing when the condition is not properly met.
Consider the case where a scheduled event is scheduled at 2:30 AM, if scheduled events were not interval based this event would be executed twice when the clock is set back an hour, and not at all when the clock is set forward an hour.
A workaround for this is to create two scheduled events with an hour time difference and do a DST check in your microflow. Create two datetime variables one with datetime and one with datetimeUTC on the current datetime. In the first microflow exit when the difference is two and in the other microflow exit when the difference is one. This way you always have one microflow on the right time independent of the DST.
And changing the Scheduled event to the current day also fix this, but then you have to manually change the date everytime DST is changing.